A not so serious video
An important thing about CNG is it can be retrofitted to most existing vehicles, although a vehicle designed for CNG would be more efficient. The gasoline or diesel fuel system is still available if you run low on CNG. CNG is sold based on GGE – Gasoline Gallon Equivalent, roughly 126 cubic feet at normal pressure. Natural gas is priced in 1000 cubic feet. Residential natural gas is currently about $9.66
That makes CNG cost about $1.21 per GGE. Regular gasoline was $2.09 yesterday (which includes gasoline taxes)
The guy on the film does make an error however. CNG does “have carbon”. Gasoline and CNG produce the same amount of CO2. CNG engines still produce carbon monoxide and Nitrous oxides, just at lower levels. Offsetting that is methane isn’t 100% consumed, so some methane comes out the tailpipe, so don’t suck your tailpipe to get high. When technology improves to stop using gasoline technology to burn CNG, that goes away.
http://evworld.com/article.cfm?storyid=1756
Exxon is working on improving the technology behind fuel cells. A fuel cell out in your driveway to recharge the all electric car overnight solves many of the issues of using electricity from the grid.